Below is a long version of what the face looks like with
lenses from a 35MM full frame DSLR, 24x36mm chip, at various focal lengths accounting
for framing with distance (moving closer or further to the subject) here you
can see the images in a tile, two rows to better see the comparison TILEPAGE
and here you can see some larger versions one by one to compare up close. THUMBNAILS
Read below the image to get a feel for distance to face of a lens at various
settings.

1 inch above head to nipple line of average large (tall) woman,
average 6'2inch male, 18 1/2 inches

Now realize, if the background were behind them by several 3 1/2 feet
the angle of view would mean if you gave 1 inch head clearance your image would
have approximately 5 inches above the head in frame.

Look at my work and the close up face shots for some great examples of long
lenses and the flattened face you all say is present and tell me if a bigger
nose and further backset ears would be better for you.

By comparison a 50MM on the same 35MM format Full Frame
gives the following realize that a full face as stated above from tip of the
head to the chin is 10 1/2 inches you would need to be almost but not quite
1 foot from the subject just to fit the whole head in frame, and closer if you
crop into the head at all

50mm ___24inches at 3 feet 36inches

50mm____17inches at 2 feet or 24inches

50mm ____9.5inches at 1 foot or 12inches

I suggest you try this at the next shoot. Take a len
maybe a zoom is best, and shoot the same straight on face shot at the widest
you can get (maybe 24mm) than again at say 35mm, than at 50mm than at 100mm
than at the longest you can get maybe 200 or better 300mm and keep the framing
of the head and face the same for all shots, that's important to see this easily.
It does not take a lot of room really if you are shooting a face top to bottom,
so you do not need a huge studio to try this. Important things to do is keep
the same framing of the face for all shots and keep the lighting the same for
all the shots, you may need an extension tube or close up step to keep the same
framing on all shots with all the lenses as some may not allow you to focus
as close as you would need too.

Next with the face in the same framing, look through
the images one by one to see the face change dramatically. That will make you
more aware of what to look for, and also determine what your preferences are.
OR BETTER YET CHECK HERE
OR EVEN HERE

Yes, moving in closer allows for you to cheat perspective
at times, as there is no reference to go by, but in general if their is a reference
like a nose, ears, eyes, forehead, there is perspective that alters and the
viewer can see it, it may be what you want, or it may not, you choose how to
use it and for what purpose. There is no right or wrong, only what you want
to achieve and get across to the viewer.